Perancangan Punch dan Die Trimming untuk Rear Grab Rail Sepeda Motor

Arif Pratama, Ir. Budi Basuki, S.T., M.Eng.

2026 | Tugas Akhir | D4 TEKNOLOGI REKAYASA MESIN

Perubahan geometri pada part Rear Grab Rail sepeda motor menyebabkan punch dan die trimming yang digunakan pada model sebelumnya tidak dapat digunakan kembali sehingga proses trimming dilakukan secara manual. Kondisi tersebut mengakibatkan peningkatan cycle time, kebutuhan tenaga kerja, serta ketidakstabilan posisi benda kerja yang berdampak pada meningkatnya potensi produk cacat. Penelitian ini bertujuan untuk merancang punch dan die trimming yang sesuai dengan geometri part model baru serta menganalisis kekuatan dan ketahanan struktur tooling menggunakan metode Finite Element Analysis (FEA).

Perancangan dilakukan menggunakan perangkat lunak Computer Aided Design (CAD) berdasarkan geometri part hasil proses High Pressure Die Casting (HPDC). Material SS400 digunakan sebagai material utama struktur tooling, sedangkan Brass C36000 digunakan sebagai insert pada area pemotongan. Gaya pemotongan dihitung berdasarkan panjang cutting edge, ketebalan material Aluminium Alloy ADC12, dan tegangan geser material, kemudian digunakan sebagai pembebanan pada simulasi Static Structural dan Fatigue menggunakan ANSYS Workbench. Parameter yang dianalisis meliputi Equivalent (von-Mises) Stress, Total Deformation, Safety Factor, Fatigue Life, Fatigue Damage, Equivalent Alternating Stress, dan Fatigue Safety Factor.

Hasil simulasi menunjukkan bahwa tooling punch overflow menerima tegangan maksimum sebesar 34,272 MPa dengan deformasi maksimum 0,35387 mm dan faktor keamanan minimum 7,1487. Tooling punch gate menghasilkan tegangan maksimum 48,669 MPa, deformasi maksimum 0,087923 mm, dan faktor keamanan minimum 5,034. Sementara itu, Lower die mengalami tegangan maksimum sebesar 104,22 MPa, deformasi maksimum 0,19997 mm, dan faktor keamanan minimum 2,3507, sehingga seluruh nilai tegangan masih berada di bawah tegangan luluh material SS400. Analisis fatigue menunjukkan umur lelah tooling berada pada rentang 1 × 10? hingga 1 × 10? siklus, dengan Fatigue Damage maksimum 0,10, Equivalent Alternating Stress maksimum 59,917 MPa, dan Fatigue Safety Factor minimum 1,9689, sehingga memenuhi kriteria keamanan terhadap pembebanan berulang. Berdasarkan hasil tersebut, rancangan punch dan die trimming dinyatakan layak digunakan untuk proses trimming Rear Grab Rail sepeda motor karena memiliki kekuatan struktur dan ketahanan fatigue yang memadai.

Changes in the geometry of the Rear Grab Rail motorcycle component caused the previous trimming punch and die to become incompatible with the new product design, resulting in a manual trimming process. This condition increased cycle time, labor requirements, and workpiece instability, leading to a higher risk of product defects. This study aims to design a new trimming punch and die that conforms to the geometry of the new component and to evaluate its structural strength and durability using the Finite Element Analysis (FEA) method.The tooling was designed using Computer Aided Design (CAD) software based on the geometry of a High Pressure Die Casting (HPDC) component. SS400 steel was selected as the main structural material, while C36000 brass was used as the cutting insert. The cutting force was calculated from the cutting edge length, ADC12 aluminum thickness, and material shear strength, and then applied as the loading condition in Static Structural and Fatigue analyses using ANSYS Workbench. The evaluated parameters included Equivalent (von-Mises) Stress, Total Deformation, Safety Factor, Fatigue Life, Fatigue Damage, Equivalent Alternating Stress, and Fatigue Safety Factor.The simulation results show that the punch overflow experienced a maximum equivalent stress of 34.272 MPa, a maximum deformation of 0.35387 mm, and a minimum safety factor of 7.1487. The punch gate produced a maximum stress of 48.669 MPa, a maximum deformation of 0.087923 mm, and a minimum safety factor of 5.034. Meanwhile, the lower die experienced a maximum equivalent stress of 104.22 MPa, a maximum deformation of 0.19997 mm, and a minimum safety factor of 2.3507, indicating that the stresses remained below the yield strength of SS400 steel. Fatigue analysis predicted a fatigue life ranging from 1 × 10? to 1 × 10? cycles, with a maximum fatigue damage of 0.10, a maximum equivalent alternating stress of 59.917 MPa, and a minimum fatigue safety factor of 1.9689, confirming that the tooling satisfies the required safety criteria under cyclic loading. Therefore, the proposed trimming punch and die design is structurally safe and suitable for application in the trimming process of the Rear Grab Rail motorcycle component.

Kata Kunci : Punch dan Die Trimming, Rear Grab Rail, High Pressure Die Casting, Finite Element Analysis, Fatigue Life.